aoqi@0: /*
aoqi@0:  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: /*
aoqi@0:  * Copyright (C) 2004-2011
aoqi@0:  *
aoqi@0:  * Permission is hereby granted, free of charge, to any person obtaining a copy
aoqi@0:  * of this software and associated documentation files (the "Software"), to deal
aoqi@0:  * in the Software without restriction, including without limitation the rights
aoqi@0:  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
aoqi@0:  * copies of the Software, and to permit persons to whom the Software is
aoqi@0:  * furnished to do so, subject to the following conditions:
aoqi@0:  *
aoqi@0:  * The above copyright notice and this permission notice shall be included in
aoqi@0:  * all copies or substantial portions of the Software.
aoqi@0:  *
aoqi@0:  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
aoqi@0:  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
aoqi@0:  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
aoqi@0:  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
aoqi@0:  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
aoqi@0:  * THE SOFTWARE.
aoqi@0:  */
aoqi@0: package com.sun.xml.internal.rngom.binary;
aoqi@0: 
aoqi@0: final class PatternInterner {
aoqi@0:     private static final int INIT_SIZE = 256;
aoqi@0:     private static final float LOAD_FACTOR = 0.3f;
aoqi@0:     private Pattern[] table;
aoqi@0:     private int used;
aoqi@0:     private int usedLimit;
aoqi@0: 
aoqi@0:     PatternInterner() {
aoqi@0:         table = null;
aoqi@0:         used = 0;
aoqi@0:         usedLimit = 0;
aoqi@0:     }
aoqi@0: 
aoqi@0:     PatternInterner(PatternInterner parent) {
aoqi@0:         table = parent.table;
aoqi@0:         if (table != null)
aoqi@0:             table = (Pattern[]) table.clone();
aoqi@0:         used = parent.used;
aoqi@0:         usedLimit = parent.usedLimit;
aoqi@0:     }
aoqi@0: 
aoqi@0:     @SuppressWarnings("empty-statement")
aoqi@0:     Pattern intern(Pattern p) {
aoqi@0:         int h;
aoqi@0: 
aoqi@0:         if (table == null) {
aoqi@0:             table = new Pattern[INIT_SIZE];
aoqi@0:             usedLimit = (int) (INIT_SIZE * LOAD_FACTOR);
aoqi@0:             h = firstIndex(p);
aoqi@0:         } else {
aoqi@0:             for (h = firstIndex(p); table[h] != null; h = nextIndex(h)) {
aoqi@0:                 if (p.samePattern(table[h]))
aoqi@0:                     return table[h];
aoqi@0:             }
aoqi@0:         }
aoqi@0:         if (used >= usedLimit) {
aoqi@0:             // rehash
aoqi@0:             Pattern[] oldTable = table;
aoqi@0:             table = new Pattern[table.length << 1];
aoqi@0:             for (int i = oldTable.length; i > 0;) {
aoqi@0:                 --i;
aoqi@0:                 if (oldTable[i] != null) {
aoqi@0:                     int j;
aoqi@0:                     for (j = firstIndex(oldTable[i]);
aoqi@0:                         table[j] != null;
aoqi@0:                         j = nextIndex(j));
aoqi@0:                     table[j] = oldTable[i];
aoqi@0:                 }
aoqi@0:             }
aoqi@0:             for (h = firstIndex(p); table[h] != null; h = nextIndex(h));
aoqi@0:             usedLimit = (int) (table.length * LOAD_FACTOR);
aoqi@0:         }
aoqi@0:         used++;
aoqi@0:         table[h] = p;
aoqi@0:         return p;
aoqi@0:     }
aoqi@0: 
aoqi@0:     private int firstIndex(Pattern p) {
aoqi@0:         return p.patternHashCode() & (table.length - 1);
aoqi@0:     }
aoqi@0: 
aoqi@0:     private int nextIndex(int i) {
aoqi@0:         return i == 0 ? table.length - 1 : i - 1;
aoqi@0:     }
aoqi@0: }